Telepathy (from the Greek τηλε, tele, "distant"; and πάθεια, patheia, "feeling") is the claimed ability of humans and other creatures to communicate information from one mind to another, without the use of extra tools such as speech or body language. Considered a form of extra-sensory perception or anomalous cognition, telepathy is often connected to various paranormal phenomena such as precognition, clairvoyance and empathy.

While there have been numerous scientific experiments into telepathy over the years, no positive result has ever resisted scrutiny. Positive results have always been demonstrated to be the result of flawed methodology, statistically erroneous conclusions, or could simply not be replicated by independent researchers.

Contents

Western scientific investigation of telepathy is generally recognized as having begun with the initial program or research of the Society for Psychical Research. The apex of their early investigations was the report published in 1886 as the two-volume work Phantasms of the Living. It was with this work that the term "telepathy" was introduced, replacing the earlier term "thought transference". Although much of the initial investigations consisted largely of gathering anecdotal accounts with follow-up investigations, they also conducted experiments with some of those who claimed telepathic abilities. However, their experimental protocols were not very strict by today's standards.

In 1917, psychologist John E. Coover from Stanford University conducted a series of telepathy tests involving transmitting/guessing playing cards. His participants were able to guess the identity of cards with overall odds against chance of 160 to 1; however, Coover did not consider the results to be significant enough to report this as a positive result.

The best-known early telepathy experiments were those of J. B. Rhine and his associates at Duke University, beginning in the 1927 using the distinctive ESP Cards of Karl Zener (see also Zener Cards). These involved more rigorous and systematic experimental protocols than those from the 19th century, used what were assumed to be 'average' participants rather than those who claimed exceptional ability, and used new developments in the field of statistics to evaluate results. Results of these and other experiments were published by Rhine in his popular book Extra Sensory Perception, which popularized the term "ESP".

Another influential book about telepathy in its day was Mental Radio, published in 1930 by the Pulitzer prize-winning author Upton Sinclair (with foreword by Albert Einstein). In it Sinclair describes the apparent ability of his wife at times to reproduce sketches made by himself and others, even when separated by several miles, in apparently informal experiments that are reminiscent of some of those to be used by remote viewing researchers in later times. They note in their book that the results could also be explained by more general clairvoyance, and they did some experiments whose results suggested that in fact no sender was necessary, and some drawings could be reproduced precognitively.

By the 1960s, many parapsychologists had become dissatisfied with the forced-choice experiments of J. B. Rhine, partly because of boredom on the part of test participants after many repetitions of monotonous card-guessing, and partly because of the observed "decline effect" where the accuracy of card guessing would decrease over time for a given participant, which some parapsychologists attributed to this boredom.

Some parapsychologists turned to free response experimental formats where the target was not limited to a small finite predetermined set of responses (e.g., Zener cards), but rather could be any sort of picture, drawing, photograph, movie clip, piece of music etc.

As a result of surveys of spontaneous psi experiences which reported that more than half of these occurred in the dreaming state, researchers Montaque Ullman and Stanley Krippner at the Maimonides Medical Center in Brooklyn, New York, undertook a series of experiments to test for telepathy in the dream state.
A "receiver" participant in a soundproof, electronically shielded room would be monitored while sleeping for EEG patterns and rapid eye movements (REMs) indicating dream state. A "sender" in another room would then attempt to send an image, randomly selected from a pool of images, to the receiver by focusing on the image during the detected dream states. Near the end of each REM period, the receiver would be awakened and asked to describe their dream during that period. The researchers claim that the data gathered suggest that sometimes the sent image was incorporated in some way into the content of the receiver's dreams.

The following is a list of some notable experiments done on telepathy in modern history. Many experiments on telepathy fail to achieve notoriety because of inconclusive results. That is, they fail to confirm the hypothesis that telepathy exists.

Experimental philosophy: A Zener Card deck is created, which consists of five cards each of five different symbols. The deck is shuffled, and the possible psychic is asked to guess the identity of each card as it is drawn and viewed by a sender. In this experiment, telepathy is assumed to be weak, and only expected to give a small deviation towards correct answers.

Experimental design:J. B. Rhine, the experimenter, would sit across a table from the subject. He would shuffle the Zener Card deck, and draw cards one at a time. For each card, he would look at it and ask the psychic to guess its identity by reading his mind. A hit rate of more than 20% was taken as evidence of telepathy. Additionally, Rhine claimed that hit rates significantly below 20% were also evidence of telepathy. These were supposedly caused by a subject who didn't like him guessing incorrectly on purpose in order to spite him.

Results: Rhine claimed to have found many subjects who performed significantly above chance, and used this as evidence for telepathy. He also noted some subjects who performed significantly below chance, and this was also used as evidence for telepathy. He noted, however, that this experiment couldn't adequately distinguish telepathy from clairvoyance.[1]

Criticisms:

Use of negative results as evidence: By the laws of probability, it is expected that in a large group of subjects, some will be found to perform significantly above chance, and some will be found to perform significantly below chance. In a sample of one hundred subjects, around 5 will show 95% significance of being over chance, and about 5 will show 95% significance of being under chance. Rhine did not take this into account, and assumed that these extreme scores always indicated a telepath.

Possibility of cheating: Rhine was accused by skeptics of making the controls too lax in early experiments, allowing the subjects to cheat in some manner (though he was never accused of cheating himself). For instance, the cards used in early experiments were partially transparent, allowing the subject to get an idea of the image by focusing on the back of the card. When his phenomenal subjects were retested under stricter conditions or under the observation of a magician, they reverted to scores that weren't significantly above chance.

Statistical assumptions: While any individual card in a Zener Card deck has a 20% chance of being each of the symbols, as the cards are drawn, the probabilities are altered. If the subject were guessing perfectly randomly, the expected hit rate would still be 20%, but the psychology involved changes this. Particularly, humans are unlikely to guess the same symbol twice in a row, which combines with the effect of having a deck that causes symbol changes to be more frequent than the expected 80% to increase the chance hit rate to around 25%.[2]

Experimental philosophy: The possible psychic is asked to guess the image on cards viewed by a sender. Answers are also compared to cards one or two places before and after the current card, checking for temporal displacement effects. In this experiment, telepathy is assumed to be weak, and only expected to give a small deviation towards correct answers.[3]

Experimental design: The experimenter and sender sit in one room, which is adjoining to another room in which the receiver (the possible psychic) sits. The door is left ajar, allowing aural communication but not giving the receiver a line of sight to the experimenter or sender. Five cards, with pictures of an elephant, giraffe, lion, pelican, and zebra are shuffled and then placed in a box that can be accessed by the sender, but which cannot be viewed by the experimenter or any observers. The experimenter and sender are separated by a screen, which has a small square hole in it.

The experimenter would consult a list of random digits from 1 to 5 for each trial, and then hold up a card with that number printed on it to the hole in the screen, allowing the sender to see it. The sender would then select the card in his box corresponding to that number (the card farthest to the left was 1, and they ascended to the right), and then attempt to mentally send that image to the receiver. After a few moments, the experimenter would call out to the receiver and ask for a guess. The guess is recorded, and at the end of the run (generally 50 guesses), the sender reveals their cards, and the guesses are converted into their corresponding numbers.

The guesses are compared to the random digits for each trial, and a statistical analysis is performed. Any significant, positive deviation from chance is assumed to be caused by telepathy. This is then repeated by comparing the guesses to the random digits one and two places ahead of and behind that trial.[4]

Results: In Soal's first experiment, he was not searching for displacement effects, and found no subjects who exhibited a better-than-chance hit rate. When advised by a colleague to check for displacement effects, he rechecked the data and found two subjects who scored significantly better than chance at predicting the card that would be chosen after the one they were supposed to be guessing. Soal then designed a new experiment which declared displacement effects as part of the tested data, per scientific proceedure.[5]

In many of the sittings in the second experiment, the receiver performed significantly above chance. In one sitting, the odds against chance of these results were calculated to be 1035 to 1. The results were so striking that some skeptics immediately accused Soal of fraud without any evidence.[6]

Criticism: The criticism of these results was very focused, and claimed simply that Soal had fudged his data in order to increase the hit rate. The following is evidence used to back up this claim:

Soal claimed to have developed his lists of target numbers randomly, but no one was ever allowed to see how he did it.

In one sitting, the sender accused Soal of changing 1's to 4's and 5's on the target sheet.[7]

In 1973, Scott and Haskell tested these claims by examining the target and guess lists. They theorized that if the accusations were true, they would find:

An excess of 4's and 5's in the target list

A deficiency of 1's in the target list

An excess of hits on 4's, and 5's

A relative excess of hits on 1's

All of these were found in the data for the sitting in which the accusation took place, as well as two other sittings with different senders.[8]

The target lists used by Soal were later matched by computer with strings of digits found in log tables, except the target lists often had a 4 or 5 where the log tables had a 1.[citation needed]

Notes:

Due to the strength of the evidence for fraud in this experiment, it is generally considered to be the case today that Soal did indeed alter his data.

This experiment was offered by Alan Turing when questioned on why he believed in telepathy, saying that this had proved it. He was apparently unaware of the significant evidence of fraud in the experiment.

Experimental Philosophy: The challenge has offered a $1,000,000 prize to any applicant who can empirically prove paranormal abilities. The belief is that if these do exist in some people, they will come forward, prove it, and claim the money. Note that the challenge allows for a large variety of paranormal ability beyond telepathy to be claimed.

Experimental Design: Each individual claim generally has a different experiment designed for it, which is agreed upon by both the applicant and the James Randi Educational Foundation as being an appropriate test. A full list of applicants and the experiments designed for them can be found here.

Results: To date, no applicant has made it past the preliminary testing of the challenge.

Criticism: As the JREF has a vested monetary interest in not paying out the million dollars, many critics claim they may be unfair in their judgments. However, the JREF points out that the money currently exists in the form of bonds from Goldman Sachs and is specifically held for the challenge. It is thus not accessible to them or anyone else, so they would be no worse off financially if the money were payed out.[9]

Experimental philosophy: The possible psychic is placed in sensory deprivation, in hopes that this will make it easier to receive and notice incoming telepathic signals. In this experiment, telepathy is assumed to be weak, and only expected to give a small deviation towards correct answers.[10]

Experimental design: The receiver (a possible psychic, who is being tested) is placed in a soundproof room and sits reclining in a comfortable chair. They wear headphones which play continuous white noise or pink noise. Halves of ping pong balls are placed over their eyes, and a red light is shined onto their face. These conditions are designed to cause the receiver to enter a state similar to being in a sensory deprivation chamber.

The sender is seated in another soundproof room, and is assigned one of four potential targets, randomly selected. Typically, these targets are pictures or video clips. The sender attempts to telepathically "send" information about the target to the receiver. The receiver is generally asked to speak throughout the sending process, and their voice is piped to the sender and experimenter. This is to assist the sender in determining if their method of "sending" information about the target is working, and adjust it if necessary. Breaks may be taken, and the sending process may be repeated multiple times.

Once the sending process is complete, the experimenter removes the receiver from isolation. The receiver is then shown the four potential targets, and asked to choose which one they believe the sender saw. In order to avoid potential confounding factors, the experimenter should remain in the dark about which target was chosen until the receiver makes their choice, and multiple sets of the pictures of videos should be used in order to avoid handling cues (evidence, such smudges on an picture, that the picture was handled by the sender).

A statistical analysis of the number of correct guesses is performed, and any significant deviation from chance is attributed to telepathy using the psi assumption. Note that certain experimenters may also attribute a hit rate significantly below chance to telepathy as well, attributing it the negative attitude of the sender to telepathy.[11]

Results: Many meta-analyses performed on multiple Ganzfeld experiments claim a hit rate of between 30% and 40%, which is significantly higher than the 25% expected by chance. They then use the psi assumption to claim that this is evidence for telepathy.[12][13]

Criticisms:

Isolation - Not all of the studies used soundproof rooms, so it is possible that when videos were playing, the experimenter (or even the receiver) could have heard it, and later given involuntary cues to the receiver during the selection process.

Handling cues - Only 36% of the studies performed used duplicate images or videos, so handling cues on the images or degradation of the videos may have occurred during the sending process.[14]

Randomization - When subjects are asked to choose from a variety of selections, there is an inherent bias to not choose the first selection they are shown. If the order in which are shown the selections is randomized each time, this bias will be averaged out. However, this was often not done in the Ganzfeld experiments.[15][16]

The psi assumption - The assumption that any statistical deviation from chance is evidence for telepathy is highly controversial, and often compared to the God of the gaps argument. Strictly speaking, a deviation from chance is only evidence that either this was a rare, statistically unlikely occurrence that happened by chance, or something was causing a deviation from chance. Flaws in the experimental design are a common cause of this, and so the assumption that it must be telepathy is fallacious. This does not rule out, however, that it could be telepathy.[17]

In seeking a scientific basis for telepathy, some psi proponents have looked to aspects of quantum theory as a possible explanation of telepathy. In general, psi theorists have made both general and specific analogies between the "unaccepted unknowns" of religion and parapsychology, and the "accepted unknowns" in the quantum sciences.

However, physicists state that quantum mechanical effects apply only to objects at sub-nanometer scales, and since the physical components of the mind are all much larger than this, these quantum effects must be negligible. Still, the true definition of what is "negligible" is perhaps unclear (seeQuantum mind). Some physicists, such as Nick Herbert [1], have pondered whether quantum mechanical effects would permit forms of communication, perhaps including telepathy, that aren't dependent on "classical" mechanisms such as electromagnetic radiation. Experiments have been conducted (by scientists such as Gao Shen at the Institute of Quantum Physics in Beijing, China) to study whether quantum entanglements can be verified between human minds. Such experiments usually include monitoring for synchronous EEG patterns between two hypothetically "entangled" minds. Thus far, no conclusive evidence has been revealed.[2]

Some scientists and intellectuals, occasionally referred to by themselves or by others as "transhumanists", believe that technologically enabled telepathy, coined "techlepathy," will be the inevitable future of humanity. Kevin Warwick of the University of Reading, England is one of the leading expert proponents of this view, and has based all of his recent Cybernetics R&D around developing practical, safe devices for directly connecting human nervous systems together with computers and with each other. He believes techno-enabled telepathy will become the sole or at least the primary form of human communication in the future. He asserts that this should happen by means of the principle of natural selection, which he predicts will force nearly everybody to make use of the technology for economic and social reasons once it becomes available to all.

The mechanics of telepathy in fiction vary widely. Some fictional telepaths are limited to receiving only thoughts that are deliberately sent by other telepaths, or even to receiving thoughts from a specific other person. For example, in Robert A. Heinlein's 1956 novel Time for the Stars, certain pairs of twins are able to send telepathic messages to each other. Some telepaths can read the thoughts only of those they touch. At the opposite end of the spectrum, some telepathic characters continuously sense the thoughts of those around them and may control this ability only with difficulty, or not at all. In such cases, telepathy is often portrayed as a mixed blessing or as a curse.

Some fictional telepaths possess mind control abilities, which can include "pushing" thoughts, feelings, or hallucinatory visions into the mind of another person, or completely taking over another person's mind and body (similar to spiritual possession). Characters with this ability may or may not also have the ability to read thoughts. The Jedi mind trick is perhaps the most famous example of telepathic mind control. The X-Men movies feature several forms of mind control, performed by the mutantsCharles Xavier and Jason Stryker. Other examples include Robert 'Pusher' Modell from The X-Files and Charlie's father from Firestarter, who uses a mind control ability called "the push."